The present invention generally relates to a turbogenerator assembly of the type including a rotor core with radial winding slots and a separate coil side with winding turns located in each winding slot and insulated from each other. In particular, the present invention is directed to a novel rotor assembly construction which creates axially extending cooling channels between each coil side and adjacently disposed wall surfaces of a surrounding winding slot allowing a cooling gas to flow through the rotor assembly.
Prior art turbo-generator rotor assemblies generally provide a relatively thick coil insulation about the conductor bundle of the coil side, as shown in German Patentschrift N. 508068 published Sep. 24, 1930. Such coil insulation acts to reduce considerably the ability of the coil side to give off heat since coil insulation generally is made to endure the maximum potential between the rotor winding and the rotor core, and has a thickness substantially greater than that of the insulation between two adjacent coil turns.
Both the coil side and the surrounding coil insulation are shown in one embodiment of German Patentschrift N 508068 as being mounted in a longitudinal slot formed in the slot wedge member. This construction has proven less than completely satisfactory, in that large and fluctuating tangential forces which effect the coil side during operation of the rotor tend to break down and destroy the coil insulation located between the copper of the coil side and the metallic slot wedge. If the longitudinal slot is made with increased depth in order to provide greater surfaces for receiving tangential forces, this greatly increases the difficulty of inserting the slot wedge since the bent portions of the coil located outside the slot provide a blocking effect.
A further embodiment of German Patentschrift N 508068 suggests fixing the tangential position of the coil side and insulation by mounting each within a metallic holder which is provided with an axially extending ridge that is fitted into a corresponding slot formed on an inner surface of the slot wedge. This assembly also has proven less than satisfactory, in that an increase in the radial dimension of the slot wedge necessary for mounting the metallic holder correspondingly reduces the available coil space. Furthermore, the space occupied by the metallic holder itself reduces the space available for conductor material and insulation.
As will be discussed in detail hereafter, the present invention solves each of the above discussed problems confronting known prior art assemblies, while at the same time providing an efficient gas-cooled rotor assembly which significantly increases the available coil space of the rotor.